Variation in the aerobic demand (JOURNAL/mespex/04.02/00005768-199503000-00025/ENTITY_OV0312/v/2017-07-20T222436Z/r/image-pngO2) of submaximal running was quantified among trained and untrained subjects stratified by performance capability. Based on a retrospective analysis of seven published studies, maximal aerobic power (JOURNAL/mespex/04.02/00005768-199503000-00025/ENTITY_OV0312/v/2017-07-20T222436Z/r/image-pngO2max), and submaximal JOURNAL/mespex/04.02/00005768-199503000-00025/ENTITY_OV0312/v/2017-07-20T222436Z/r/image-pngO[sb]2[/sb] values were analyzed in three groups of trained distance runners (Category 1 (C1) (elite runners; N = 22), Category 2 (C2) (sub-elite runners; N = 41), and Category 3 (C3) (good runners; N = 16), and one group (N = 10) of untrained subjects (Category 4; C4). Results indicated that JOURNAL/mespex/04.02/00005768-199503000-00025/ENTITY_OV0312/v/2017-07-20T222436Z/r/image-pngO2max differed significantly (P < 0.05) across groups, such that C1 > C2 > C3 > C4. Analysis of submaximal JOURNAL/mespex/04.02/00005768-199503000-00025/ENTITY_OV0312/v/2017-07-20T222436Z/r/image-pngO2 data also revealed that C4 was more uneconomical than C1, C2, and C3 and that C2 and C3 were less economical than C1. Average within-group variability in submaximal JOURNAL/mespex/04.02/00005768-199503000-00025/ENTITY_OV0312/v/2017-07-20T222436Z/r/image-pngO[sb]2[/sb] was similar across categories and a marked overlap of minimum, mean and maximal economy values existed across categories. These data suggest that 1) trained subjects arc more economical than untrained subjects, 2) elite runners display better economy compared to less-talented counterparts, and 3) economical and uneconomical runners can be found in all performance categories.